Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.
The general structure of polyanilines (PANIs) is known. However, up until now, polyanilines have not been widely exploited in technological applications due to the poor processability of polyaniline, which is largely a function of its low solubility in common solvents and its poor miscibility with other polymers (H. Salavagione et al., Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 42, 5587-5599 (2004)). PANI dissolves to a significant extent in only a small number of solvents eg. N-methyl-2 pyrrolidone (NMP) or hexafluoro-2-propanol (HFP). The use of HFP also has significant cost disadvantages due to its relative expense.
Films containing PANI have recently been found to act as antibacterial materials. In Chinese patent publication CN 1844245 PANI, either as a powder or in a composite film with polyvinyl alcohol or polyethylene, is disclosed as having antibacterial activity against the growth of Escherichia coli and staphylococcal organisms. The films contained low quantities (1-10 wt %) of PANI relative to the amount of polyvinyl alcohol or polyethylene used, which is indicative of the processability problems that would prohibit higher amounts of PANI being used.
It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. More particularly, it is an object of the invention in its preferred form to provide a polyaniline polymer or copolymer which has good processability and has antimicrobial activities, in particular antibacterial and/or antifungal and/or antiviral activities.